title: Highly sensitive sandwich enzyme immunoassay of human IgE with beta-D-galactosidase from Escherichia coli.
abstract: A highly sensitive sandwich enzyme immunoassay of human IgE was developed. Polystyrene balls were coated with goat anti-human IgE immunoglobulin (IgG) by physical adsorption. Goat anti-human IgE Fab' was purified by affinity chromatography and conjugated with beta-D-galactosidase from Escherichia coli. Using thus prepared anti-IgE-coated polystyrene balls and anti-IgE-beta-D-galactosidase conjugate, 0.2 mU (2 amol)--1 U of IgE per assay could be determined. When 0.1 microliter of serum per assay was used, the range of IgE levels in serum that could be determined was 2--10000 U/ml, and even 0.01 U/ml was measurable by using 20 microliters of serum. The regression equation and coefficient for correlation to radioimmunoassay were gamma (RIA) = 0.94 chi (EIA) + 18.2 and 0.96 (n = 81), respectively. The coefficients of within- and between-assay variations ranged from 5.4 to 8.5%. The mean levels of serum IgE determined by the present assay were 103 U/ml in 70 normal children and 1064 U/ml in 38 children with bronchial asthma.
mesh_terms: D000918:Antibody Specificity; D001249:Asthma / Q000276:immunology; D002648:Child; D004926:Escherichia coli / Q000201:enzymology*; D005260:Female; D005696:Galactosidases; D006801:Humans; D007124:Immunoenzyme Techniques; D007073:Immunoglobulin E / Q000032:analysis*; D008297:Male; D013696:Temperature; D001616:beta-Galactosidase
chemical_list: D007073:Immunoglobulin E; D005696:Galactosidases; D001616:beta-Galactosidase